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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

UTRICULARIA BLADDERWORT
Carnivorous by bladders (here treated as modified leaves), into which small organisms are sucked when hairs at opening are triggered [epiphytic]. Stem: submersed or subterranean shoots [rarely caudex]; some aquatic species produce 2 kinds of stems, green (in water or at surface; leaves with flattened or thread-like segments; bladders 0–few) and white (generally buried in substrate; leaves 0; bladders many), the latter not always present in poor collections. Leaf: simple or generally dissected into narrow segments, alternate on stolon, margins often with bristles (visible at 10–30×). Inflorescence: raceme or 1-flowered, emergent; scape slender or wiry, bracts present. Flower: calyx lips 2[4], unlobed; corolla yellow [or not], with red-brown streaks or not, upper lip ± entire, lower entire or 3-lobed, spurred; rarely cleistogamous. Fruit: capsule.
± 220 species: worldwide, especially tropics, Australia. (Latin: little bag, from bladders) [Taylor 1989 Kew Bull Add Ser 14:1–724] Size variable, often unreliable for identification; distinction between stems, leaves uncertain. Glands inside bladders consist of 2 pairs of oppositely directed arms, angles of divergence between which used (at 150× or more) to identify fresh or pressed specimens. {hort link}

Key to Utricularia

1. Leaves simple, flattened; stolons subterranean; cleistogamous flowers common; bracts peltate ..... U. subulata

1' Leaves dissected into 2–many thread-like to flattened ultimate segments; stolons free-floating, loosely rooted, or subterranean; cleistogamous flowers rare; bracts attached at base

2. Stems generally of 1 kind (sometimes weakly of 2 kinds in Utricularia minor), with bladders, leaves throughout

3. Leaf 15–90 mm, ultimate segments > 30, margin bristles 0.1–0.3 mm; stem 30–150 cm; peduncle 1–3 mm diam; bladder glands with long arm-pair parallel or diverging slightly, short arm-pair diverging by 90–180° ..... U. macrorhiza

3' Leaf 2–15 mm, ultimate segments 2–22, margin bristles 0 or microscopic; stem 5–30 cm; peduncle 0.4–0.8 mm diam; bladder glands with long arm-pair diverging slightly, short arm-pair diverging slightly or by 270–300°

4. Ultimate leaf segments 2–6(8); corolla upper lip >= lower, spur ± = lower; bladder glands with both arm-pairs diverging slightly ..... U. gibba

4' Ultimate leaf segments 7–22; corolla upper lip, spur both <= 1/2 × lower lip; bladder glands with long arm-pair diverging slightly, short arm-pair diverging by 270–300° (so all 4 arms oriented in same direction) ..... U. minor (2)

2' Stems clearly of 2 kinds, green (in water or at surface; leaves with flattened or thread-like segments; bladders 0–few) and white (generally buried in substrate; leaves 0; bladders many)

5. Ultimate leaf segment margins without bristles; leaf segments ± thread-like to flattened; corolla 6–8 mm; bladder glands with long arm-pair diverging slightly, short arm-pair diverging by 270–300° (so all 4 arms oriented in same direction) ..... U. minor (2)

5' Ultimate leaf segment margins with bristles 2–12, 0.08–0.16 mm; leaf segments flattened; corolla 1–1.6 cm; bladder glands with long arm-pair diverging by 0–45°, short arm-pair diverging by 0–160°

6. Ultimate leaf segment margins with 5–12(20) bristles, ± entire; leaf segment tips obtuse; bladders on leafless shoots, rarely on leafy shoots; corolla spur < or ± = lower lip; bladder glands with both arm-pairs diverging by generally 0–30° ..... U. intermedia

6' Ultimate leaf segments margins with 1 bristle on each of 2–7(10) teeth; leaf segment tips acute; bladders on leafless shoots, also often ± few on leafy shoots; corolla spur ± 1/2 × lower lip; bladder glands long arm-pair diverging by 20–45°, short arm-pair diverging by 40–160° ..... U. ochroleuca

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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